North Carolina Administrative Code
Title 15A - Environmental Quality
Chapter 02 - ENVIRONMENTAL MANAGEMENT
Subchapter B - SURFACE WATER AND WETLAND STANDARDS
Section .0200 - CLASSIFICATIONS AND WATER QUALITY STANDARDS APPLICABLE TO SURFACE WATERS AND WETLANDS OF NORTH CAROLINA
Section 02B .0277 - FALLS RESERVOIR WATER SUPPLY NUTRIENT STRATEGY: STORMWATER MANAGEMENT FOR NEW DEVELOPMENT
Universal Citation: 15A NC Admin Code 02B .0277
Current through Register Vol. 39, No. 6, September 16, 2024
The following is the stormwater strategy, as prefaced in 15A NCAC 02B .0275, for new development activities within the Falls watershed:
(1) PURPOSE. The purposes of this Rule are as follows:
(a) To achieve and maintain the nitrogen and
phosphorus loading objectives established for Falls Reservoir in
15A NCAC
02B .0275 from lands in the Falls watershed
on which new development occurs;
(b) To provide control for stormwater runoff
from new development in Falls watershed to ensure that the integrity and
nutrient processing functions of receiving waters and associated riparian
buffers are not compromised by erosive flows; and
(c) To protect the water supply, aquatic life
and recreational uses of Falls Reservoir from the potential impacts of new
development.
(2) APPLICABILITY. This Rule shall apply to those areas of new development that lie within the Falls watershed and the planning jurisdiction of a municipality or county that is identified in 15A NCAC 02B .0275. This Rule shall not apply to development activities on state and federal lands that are set out in Rule .0281 of this Section.
(3) REQUIREMENTS. All local governments subject to this Rule shall develop stormwater management programs for submission to and approval by the Commission, to be implemented in areas described in Item (2) of this Rule. Nothing in this Rule preempts local governments from establishing requirements that are more restrictive than those set forth in this Rule. Local government stormwater management programs shall include the following elements and the standards contained in Item (4):
(a) The
requirement that a stormwater management plan shall be submitted for local
government approval based on the standards in Item (4) for all proposed new
development disturbing one-half acre or more for single family and duplex
residential property and recreational facilities, and 12,000 square feet or
more for commercial, industrial, institutional, multifamily residential, or
local government property;
(b) A
plan to ensure maintenance of best management practices (BMPs) implemented to
comply with this rule for the life of the development; and
(c) A plan to ensure enforcement and
compliance with the provisions in Item (4) of this Rule for the life of the new
development.
(4) PLAN APPROVAL REQUIREMENTS. A developer's stormwater plan shall not be approved by a subject local government unless the following criteria are met:
(a) Nitrogen and phosphorus loads contributed
by the proposed new development activity shall not exceed the following
unit-area mass loading rates for nitrogen and phosphorus, respectively,
expressed in units of pounds/acre/year: 2.2 and 0.33. Proposed development that
would replace or expand structures or improvements that existed as of December
2006, the end of the baseline period, and that would not result in a net
increase in built-upon area shall not be required to meet the nutrient loading
targets or high-density requirements except to the extent that the developer
shall provide stormwater control at least equal to the previous development.
Proposed development that would replace or expand existing structures or
improvements and would result in a net increase in built-upon area shall have
the option either to achieve at least the percentage loading reduction
objectives stated in
15A NCAC
02B .0275 as applied to nitrogen and
phosphorus loading from the previous development for the entire project site,
or to meet the loading rate targets described in this Item. These requirements
shall supersede those identified in
15A NCAC
02B .0104(q). The developer
shall determine the load reductions needed to meet these loading rate targets
by using the loading calculation method called for in Sub-Item (5)(a) or other
equivalent method acceptable to the Division;
(b) The developer shall have the option of
offsetting part of the nitrogen and phosphorus load by implementing or funding
offsite offset measures. Before using an offsite offset option, a development
shall implement onsite structural stormwater controls that achieve one of the
following levels of reductions:
(i) Proposed
new development activity disturbing at least one-half acre but less than one
acre of land for single family and duplex residential property and recreational
facilities, except as stated in Sub-Item (4)(b)(iv), shall achieve 30 percent
or more of the needed load reduction in both nitrogen and phosphorus loading
onsite and shall meet any requirements for engineered stormwater controls
described in Sub-Item (4)(e) of this Rule;
(ii) Proposed new development activity
disturbing at least 12,000 but less than one acre of land for commercial,
industrial, institutional, multifamily residential, or local government
property, except as stated in Sub-Item (4)(b)(iv), shall achieve 30 percent or
more of the needed load reduction in both nitrogen and phosphorus loading
onsite and shall meet any requirements for engineered stormwater controls
described in Sub-Item (4)(e) of this Rule;
(iii) Except as stated in Sub-Item
(4)(b)(iv), proposed new development activity that disturbs one acre of land or
more shall achieve 50 percent or more of the needed load reduction in both
nitrogen and phosphorus loading onsite and shall meet any requirements for
engineered stormwater controls described in Sub-Item (4)(e) of this Rule;
or
(iv) Proposed development that
would replace or expand structures or improvements that existed as of December
2006 and that increases impervious surface within a local government's
designated downtown area, regardless of area disturbed, shall achieve 30
percent of the needed load reduction in both nitrogen and phosphorus onsite,
and shall meet any requirements for engineered stormwater controls described in
Sub-Item (4)(e) of this Rule;
(c) Offsite offsetting measures shall achieve
at least equivalent reductions in nitrogen and phosphorus loading to the
remaining reduction needed onsite to comply with the loading rate targets set
out in Sub-Item (4)(a) of this Item. A developer may use any measure that
complies with the requirements of Rules .0703 and .0282 of this
Subchapter;
(d) Proposed new
development subject to NPDES, water supply, and other state-mandated stormwater
regulations shall comply with those regulations in addition to the other
requirements of this Sub-item. Proposed new development in any water supply
watershed in the Falls watershed designated WS-II, WS-III, or WS-IV shall
comply with the density-based restrictions, obligations, and requirements for
engineered stormwater controls, clustering options, operation and maintenance
responsibilities, vegetated setbacks, land application, and landfill provisions
described in Sub-Items (3)(b)(i) and (3)(b)(ii) of the applicable rule among
15A NCAC
02B .0214 through
02B .0216. Provided, the
allowance in water supply watershed rules for 10 percent of a jurisdiction to
be developed at up to 70 percent built-upon area without stormwater treatment
shall not be available in the Falls watershed;
(e) Stormwater systems shall be designed to
control and treat at a minimum the runoff generated from all surfaces in the
project area by one inch of rainfall. The treatment volume shall be drawn down
pursuant to standards specific to each practice as provided in the July 2007
version of the Stormwater Best Management Practices Manual published by the
Division, or other at least technically equivalent standards acceptable to the
Division;
(f) To ensure that the
integrity and nutrient processing functions of receiving waters and associated
riparian buffers are not compromised by erosive flows, at a minimum, the new
development shall not result in a net increase in peak flow leaving the site
from pre-development conditions for the one-year, 24-hour storm
event;
(g) New development may
satisfy the requirements of this Rule by meeting the post-development
hydrologic criteria set out in Chapter 2 of the North Carolina Low Impact
Development Guidebook dated June 2009, or the hydrologic criteria in the most
recent version of that guidebook;
(h) Proposed new development shall
demonstrate compliance with the riparian buffer protection requirements of
15A NCAC
02B .0233 and
02B .0242 or subsequent
amendments or replacements to those requirements.
(5) RULE IMPLEMENTATION. This Rule shall be implemented as follows:
(a) No later than
March 15, 2011, the Division shall submit a model local stormwater program,
including a model local ordinance that embodies the criteria described in Items
(3) and (4) of this Rule to the Commission for approval. The model program
shall include a tool that will allow developers to account for nutrient loading
from development lands and loading changes due to BMP implementation to meet
the requirements of Items (3) and (4) of this Rule. The accounting tool shall
utilize nutrient efficiencies and associated design criteria established for
individual BMPs in the July 2007 version of the Stormwater Best Management
Practices Manual published by the Division, or other more precise standards
acceptable to the Division. At such time as data quantifying nutrient loads
from onsite wastewater systems is made available, the new development nutrient
export accounting tool shall be revised to require accounting for nutrient
loading from onsite wastewater from newly developed lands that use such
systems. Should research quantify significant loading from onsite wastewater
systems, the Division may also make recommendations to the Commission for
Public Health to initiate rulemaking to reduce nutrient loading to surface
waters from these systems. The Division shall work in cooperation with subject
local governments and other watershed interests in developing this model
program;
(b) Within five months
after the Commission's approval of the model local stormwater program and model
ordinance, subject local governments shall submit stormwater management
programs, in conjunction with similar requirements in
15A NCAC
02B .0278, to the Division for preliminary
approval. These local programs shall meet or exceed the requirements in Items
(3) and (4) of this Rule;
(c)
Within 10 months after the Commission's approval of the model local stormwater
program, the Division shall provide recommendations to the Commission on local
stormwater programs. The Commission shall either approve the programs or
require changes based on the standards set out in Items (3) and (4) of this
Rule. Should the Commission require changes, the applicable local government
shall have two months to submit revisions, and the Division shall provide
follow-up recommendations to the Commission within two months after receiving
revisions;
(d) Within six months
after the Commission's approval of a local program, or upon the Division's
first renewal of a local government's NPDES stormwater permit, whichever occurs
later, the affected local government shall complete adoption of and implement
its local stormwater management program; and
(e) Upon implementation, subject local
governments shall submit annual reports to the Division summarizing their
activities in implementing each of the requirements in Items (3) and (4) of
this Rule, including changes to nutrient loading.
(6) EQUIVALENT PROGRAM OPTION. A local government may in its program submittal under Sub-Item (5)(b) of this Rule request that the Division accept the local government's implementation of another stormwater program or programs as satisfying one or more of the requirements set forth in Items (3) and (4) of this Rule. The Division shall provide determination on the acceptability of any such alternative prior to requesting Commission approval of local programs as required in Sub-Item (5)(c) of this Rule. Should a local government propose alternative requirements to achieve and maintain the rate targets described in Sub-Item (4)(a) of this Rule, it shall include in its program submittal technical information demonstrating the adequacy of those requirements. Should an alternative program propose monitoring of watersheds to compare measured loading to expected loading, it shall at a minimum include the following:
(a) Engineering calculations that quantify
expected loading from new development projects based on stormwater controls
currently enforced;
(b) At least
three years of continuous flow and nutrient monitoring data demonstrating that
watershed loading rates are at or below rates that would result from meeting
the requirements of this Rule and Rule .0278 of this Section based on the land
cover composition of the watershed;
(c) An ongoing water quality monitoring
program based on continuous flow and concentration sampling to be performed
indefinitely into the future with results reported annually to the Division for
review and approval;
(d) A
corrective action plan to be implemented should data collected under the
ongoing monitoring program demonstrate watershed loading is within 10 percent
of the rate estimated in compliance with this Item; and
(e) Should a local government submit an
alternate program for consideration that includes areas within its jurisdiction
outside of the monitored watershed it shall submit technical information
demonstrating the areas outside of the monitored watershed can reasonably be
expected to load at equal or lesser rates than those estimated in compliance
with this Item based on comparative analysis of land uses and other factors
affecting nutrient loading.
Authority
G.S.
143-214.1;
143-214.3;
143-214.5;
143-214.7;
143-215.1;
143-215.3;
143-215.3(a)(1);
143-215.6A;
143-215.6B;
143-215.6C;
143-215.8B;
143B-282(c);
143B-282(d);
S.L. 2005-190; S.L. 2006-259; S.L. 2009-337; S.L. 2009-486;
Eff.
January 15, 2011 (this permanent rule replaces the temporary rule approved by
the RRC on December 16, 2010);
Amended Eff. April 1,
2020.
Disclaimer: These regulations may not be the most recent version. North Carolina may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google
Privacy Policy and
Terms of Service apply.
